Traversing mechanism

ABSTRACT

A traversing mechanism for strands comprising a series of cams mounted for rotation about an axis. Inclined working faces of the cams cooperate with faces parallel to the axis of rotation to traverse the strand over a path which maintains an essentially constant spacing from the axis of rotation during all traversing positions.

O United States Patent 1 1 3,784,121 Arno et al. Jan. 8, 1974 [54] TRAVERSING MECHANISM 3,292,872 12/1966 Hayden 242 43 [75] Inventors: David Michael Arno, Toledo; John p Maumee both of Primary Examiner-Stanley N. Gilreath Ohlo Att0meyJ0hn A. McKinney and Robert M. Krone [73] Assignee: Johns-Manville Corporation, New

York, NY.

[22] Filed: Mar. 2, 1971 [57] ABSTRACT 21 A l. N 120,260 1 pp 0 A traversing mechanism for strands comprising a series of cams mounted for rotation about an axis. In- [52] U.S. CL 242/43, 242/18 G clined working faces of the 331115 cooperate with faces [5]] Int. Cl B6511 54/28 parallel to the axis of rotation to traverse the strand [58] Fleld of Search 242/43, 13 G ov r a path which aintains an essentially constant spacing from the axis of rotation during all traversing [56] References Cited positions UNITED STATES PATENTS 3.040.999 6/1962 Hayden et a1 242/43 14 Claims, 12 Drawing Figures I IO I 102 78 e4 F 7 2 I L PAIENTED 8 SHEET 1 BF 2 m0 mm WA mm M Ll l M D m D JOHN GILBERT MOHR ATTORNEYS PAIENTEDJAN sum 3.784. 1 21 sum 2 or 2 FIG. 6A

FIG. 6B

WW6. 5C

" FIG.5D

FlG. 6E

F IG. 6 F

INVENTORS DAVID MICHAEL ARNO JOHN GILBERT MOHR ATTORNEYS TRAVERSING MECHANISM SUMMARY The present apparatus relates to traverse mechanism and more particularly to traverse mechanism for imparting a traversing motion to a strand passing in contact therewith prior to being wound into a multilayered package. The traverse mechanism consists of a plurality of cams radially mounted on equal spacing about the axis of rotation paralleling that of the traverse mechanism. Generation of a surface inclined to the axis of rotation, which advances helically at a decreasing angle of inclination in moving away from the longitudinal center or neutral strand position of the face of the traverse mechanism, and of a surface having 'a minor diameter occur upon rotation of the traverse mechanism by virtue of parallel and inclined portions of the cams. The surfaces for diametrically opposed cams have opposed inclinations. Adjacent cams alternately engage the strand at both the minor diameter and one of the inclined surfaces to move the strand over the face of the traverse mechanism. Thus, the strand is moved in alternately opposed directions along a traversing path paralleling the axis of rotation of the traverse mechanism.

As a result of the above traverse mechanism a method of winding fibrous strand into a package can consist of the steps providing a plurality of fibers, advancing the fibers longitudinally to be gathered into a strand, moving the strand by virtue of winding it upon a package while imparting traverse motion to the strand which is both progressive and regressive, scribing a path parallel to the axis of rotation of the package being wound by the traversing motion of the strand, and collecting the strand into a common package.

The traverse mechanism and method for winding the strand increase rovings efficiency by decreasing filamentation and disappearing ends while maintaining strand slope to discourage flattened strands. The package produced is, therefore free of overlap. In addition, package wrap and shape is enhanced by the constant tension maintained by continued contact of the strand on a constant minor diameter of the traverse mechanism which eliminates radial deviation of the strand by maintaining a constant angle of approach and departure therefrom.

BACKGROUND OF THE INVENTION This invention relates to strand traverse mechanisms for strand winding equipment wherein the traverse mechanisms cause the strand to travel across the face of the package of strand being wound.

It has been known in thelprior art that packages of strand wound using a traverse mechanism to achieve greater separation of the strands as wound, by causing intersections of rows and layers of strand within the package at angles sufficient to avoid placement of strands in parallelism, form a package which is easy to unwrap when the strand is to be used. As shown in G. Beach U.S. Pat. No. 2,391,870, issued Jan. 1, 1946, and entitled TRAVERSING MECHANISM the traverse mechanism can consist of substantially spirally shaped complimentary cam wires on a shaft, or a cylinder suitably secured to an arm or shaft so that the longitudinal axis of the cylinder and arm form an acute angle at their point of intersection as illustrated in S. R. Genson U.S. Pat. No. 3,399,841 issued Sept. 3, 1968, and

entitled STRAND TRAVERSING DEVICE. A series of cam wires has also been used as well as cam surfaces of a continuous nature which are at a constant oblique angle to the longitudinal axis of the traverse mechanism. The R.L. Hayden et al U.S. Pat. No. 3,040,999 issued June 26, 1962, and entitled APPA- RATUS FOR PACKAGING A STRAND OF FLEXI- BLE MATERIAL illustrates both of the above concepts.

The cam wires generate a surface matching that of a continuous cam surface when the traverse mechanism to which the cam wires are attached is rotated about its longitudinal axis.

In all the above apparatus of the prior art, the strand is caused to move laterally along the traverse mechanism, by sliding along the cam surface as the traverse mechanism is rotated, at a point of general tangency between the strand and the traverse mechanism. Impetus is imparted to the strand in the traversing direction by cam surfaces inclined to the axis of rotation of the traverse mechanism as each point of contact of the surfaces with the strand passes the point of general tangency between the strand and the traverse mechanism. With a constant angle inclination of the cam surfaces to the axis of rotation the strand is caused to traverse by sliding down the inclined surface. Thus, the strand is displaced both longitudinally and radially outward and inward with respect to the longitudinal axis of the traverse mechanism.

The tension in the strand increases with both the amount of the deviation in the radial direction and the amount of wrap around the traverse mechanism. Thus, the prior art imposed a variation in tension on the strand due to the traverse action.

The strand tension increase resulting from the radial deviation of the strand is a repetitive phenomenon occurring upon each half revolution winding a package causes the layers on the package to become more tightly and subsequently less tightly wound throughout the package. In addition, the tighter windings of strand are caused to widen or flatten out resulting in successive layers being overlapped and virtually tied together. The strands are not free for unwinding from the package when used in subsequent production operations because of the overlapping.

The combination of tension increase on the strand and the change in angle of approach of the strand to the package from deviation of the strand encourages filamentation or disappearing ends.

Increase in tension on the strand caused by radial spacing deviation thereof increases resistance to the traversing motion by the strand as the extreme limits of travel are reached. An inclined cam surface alone gives no positive assurance of full traversing travel in overcoming the strand resistance, and should the strand resist travel and become momentarily stationary the strand filaments tensile strength may be reduced as a result of the abrasion of the cam surfaces rotating against the stationary strand.

The present traverse mechanism is directed at the above tension, wrap, traversing and strand shaping problems. Contact with the traverse mechanism by the strand at the point of tangency between the two is maintained at a constant radius to overcome strand deviation and accompanying tension and wrap problems. Provisions for positive traversing of the strand as well as its shaping are provided to overcome resistance to traversing motion and maintain strand shape.

BRIEF DESCRIPTION OF THE DRAWINGS strand on the traverse mechanism in 60 increments of rotation of the traverse mechanism; and

FIGS. 6A through 6G are another presentation of the functions of the cams at various angular relationships to the strand being displaced laterally.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, FIG. 1 illustrates the traversing mechanism, generally indicated by numeral 10, in conjunction with apparatus for forming continuous glass filaments comprising a glass melting bushing 12 from which a plurality of exudations 14 issue. The exudations 14 are attenuated into a plurality of filaments 16 by means of a rotating tube or spool 18 mounted for rotation on mandrel 20. Converging of the filaments 16 into one or more strands 22 is accomplished on one or more convergers 24.

The traversing-mechanism and method of the preferred embodiment illustrated is particularly adapted for use with the formation of heat-softenable continuous filaments 16, such as glass, and hence will be described in connection therewith. Clearly, the mechanism and method are not limited to glass filament strands nor to any particular strand but are also applicable to the winding of any type strand into a package 26 on a spool 18.

The traversing mechanism 10, to be described in detail below, is positioned to engage the strand 22 between the convergers 24 and the mandrel 20.

The spool 18, or tubular core, which serves as the base for the package 26 being formed, is removably mounted on mandrel for rotation therewith. Mandrel 20 is shown to be supported by and rotatable with shaft 28 driven by motor 30. Reciprocation of the winder assembly 31 parallel to the axis of rotation of mandrel 20, in a direction 32 is accomplished by mounting the motor upon a slidable guide 34. Suitable known means (not shown) are used to move the motor 30. Reciprocation of winder 31 and consequently of winding tube or core 18 effects a traverse movement of the strand 22 across the face of the package 26 being formed. The traverse mechanism effects a series of progressive and regressive bights across the package 26 being formed whereas the reciprocation of the winder 31 and core 18 effects an end-to-end progression of a series of bights to form successive layers extending the length of the package to be formed with one layer being formed during each winder stroke.

The traverse mechanism 10 comprises a tube 36 with concentric terminal flanges 38 and 40 only slightly larger in diameter than the tube 36 as illustrated in FIGS. 3 and 4. The reduced diameter flanges result in material reductions in the mass of the traverse mechanism which is desirable at high speeds, but where strength is a governing consideration over speed, larger flanges can be used. The tube bore 42 extends through the flanges 38 and 40 and is adapted to receive the drive shaft 44 which can be either the shaft of motor 46 in FIG. 1, or a separate shaft coupled thereto. Further, where multiple packages 26 are wound on a common mandrel 20, matching multiple traverse mechanisms 10 can be mounted on a common drive shaft 44. Securing of the tube 36 to the drive shaft 44 is accomplished by one or more set screws 46 engaging threads formed in a like number of holes 48 penetrating the wall of the flange 38.

Two series of wires 50, 52 and 54, and 56, 58 and 60, three to a series, and illustrated in the preferred embodiment as shaped rods or wires 66 are angularly spaced at 60 intervals and extend radially from the axis of rotation of the traverse mechanism around the flanges 38 and40 with the wires comprising each series in radial opposition to the wires of the other series. The cam defining surfaces can be of various forms as the edges of sheets or as continuous surfaces or semicontinuous surfaces. While six wires are the preferred number for a traverse mechanism, the cam array can be made up of other groupings of wires in even numbers. Typical of a wire for use a cam is 0.125 inch phosphor bronze wire, but other wire may be used for the cams.

Taken in the order in which the wires successively engage the strand 22, the wires comprising the first series of cams are respectively indicated by numerals 50, 52 and 54. The wires comprising the second series of cams are respectively indicated by numerals 56, 58 and 60. Each of the wires 50 through 60 taken in ascending numerical order includes a strand contacting incline surface respectively numbered 62, 64, 66, 68, 70 and 72, a portion parallel to the axis of rotation of traverse 10 respectively numbered 100, 102, 104, 101, 103 and 105, and a contacting right angle surface respectively numbered 76, 78, 82 and 84 on all except wires 50 and 56. The radial extremities of the wires 50 and 52, which along with wire 54 comprise the first cam array, are respectively extended by legs 100, 102, and 104 paralleling the axis of the tube 36 and then entering blind holes 106, 108 and 110 in the side of flange 38 in angular alignment with blind holes 90, 92 and 98 on flange 40. The wires are secured to the flanges 38 and 40 at the radially oriented legs 90, 92 and 94 by known methods, for example, by set screws 112.

The wires 56, 58 and 60 comprising the second series of cams are respectiveiy identical in configuration to the cams 50, 52 and 54 of the first series of cams located diametrically opposed to matching wires of the first series but reversed so that the inclined surfaces of the two series are in opposition to each other.

Strand motion developed by the traverse is generally of a constant angular contact from a point of tangency to the converge'r 24 to the traverse 10 to a point of tangency to the strand package 26 with a range of lateral displacement parallel to the axis of rotation of traverse 10 of about one and one half inch in the exemplary embodiment. The form of the path of lateral displacement of the strand is generally sinusoidal as represented in FIGS. 6A to 6G, and is centered about a neutral line defined by the position the strand would assume if unconstrained laterally by the traverse in its travel from converger 24 to package 26. While the traverse is effective, it causes the strand to accelerate in traverse travel toward the neutral axis and decelerate in traverse travel as it moves from the neutral axis toward its outer limit. Thus, as it crosses the neutral axis its lateral velocity is maximum and its lateral velocity is minimum at the extremes of traverse.

Strand forces tend to aid lateral displacement toward the neutral axis. Therefore, the cams are arranged to impart their maximum lateral vector forces on the strand as it is carried across the neutral axis and their minimum vector forces at the extremes of lateral travel. Such vector forces are imparted to the strand as it is initially contacted by the inclined surfaces of the cam wires during the rotation of those wires around the axis of the traverse mechanism and continues as the strand progressively slides along that wire toward the axis. The strand position at the moment it is directed to the package 26 is fixed at the point the strand is in engagement with the portion of the wire parallel to the axis. In the case of those wires which impart the greater lateral force to the strand, wires 52 and 54 and wires 58 and 60, a right angle portion positively cradles the strand in this fixed position by causing the strand to drop abruptly and positively from the inclined surface to the surface of minimum radius. The intersection of camming surfaces at right angles supports the strand on two sides while it is subjected to the greater lateral displacing forces whereby the tendency of the strand to flatten toward a ribbon form is opposed. In the case of the return of the strand toward its neutral axis, the lateral force inherent in tending to return the strand requires only a small augmenting force from the cam, hence the wires 50 and 56 have an inclination which imparts only a small lateral force and no offset to function as a positive strand positioner.

Upon rotation of the traverse mechanism 10 the outer surfaces of legs 100, 102 and 104 of the first series of cams as well as the matching legs 101, 103, 105 of the second series of cams generate a minor diameter which defines the depth at which the strand 22 departs from the traverse mechanism in its travel to forming tube 18, as indicated by point A in FIG. 2. In practice, the traversing mechanism 10 is mounted with the cams centered laterally on the neutral axis of the strand 22. Thus, the right angle surfaces 76 and 82 are spaced across the neutral axis essentially the width of the strand as best seen in FIGS. 6A, 6D and 66. Three wires of the first series of cams consecutively contact the strand in order of rotation, respectively designated by the numerals 50, 52 and 54, as shown in FIGS. 6F, 66 and 68, so that the strand contacting faces progressively advance toward the opposed flange 38 at regularly spaced intervals with a portion ofeach cam surface adjacent the minor diameter in rotationally overlapping relation to a like portion of a succeeding cam wire strand contacting surface. Therefore, the strand contacting surfaces of the wires 50, 52 and 54 lie with a 120 sector, however, upon rotation in the direction previously designated, each cam in recited order contacts the strand 22 over an arc of its travel to progressively move the strand to the left, which direction is away from the flange 40 toward the flange 38. Collectively, the wires 50, 52 and 54 progressively move the strand 22 approximately 1% inch. Conversely, the wires 56, 58 and 60 move the strand to the right. Two

surfaces on wire 52 and 54 are strand contacting surfaces, i.e., the right angle and inclined surfaces respectively indicated by numerals 76 and 64 and 78 and 66.

The part of the right angle surfaces 76 and 78 paralleling the axis of rotation conforms to the minor diameter generated by the cams, while the remaining part provides a positive stop against which the strand 22 cannot regress. Since wire 50 contacts the strand 22 at a strand position where the strand 22 has a natural tendency to return from its extreme point of traversing travel back toward a neutral position, i.e., where a straight line path exists for the strand between the converger 24 and core 18 of FIG. 1, only an inclined surface 62 is provided for the wire 50. Contact between the strand 22 and the traverse mechanism 10 is continuous at the point of tangency, point A of FIG. 2 where the strand 22 partially wraps the traverse mechanism 10 for a sector of 30 to 50 in general conformity with, and in contact with, the minor diameter generated by the cams. One of the advantages of the traverse mechanism 10 is in maintaining the strand 22 on the minor diameter at all times whereby deviation of the strand 22 radially with respect to the axis of rotation is eliminated and the angle of departure of the strand 22 from the traverse mechanism 10 is not changed by operation of the traverse mechanism 10 other than to traverse the strand 22 across the face thereof.

The two parts of the right angle surface, i.e., that conforming with the minor diameter and that providing a positive stop, are joined by a radius which helps the strand 22, especially those of a large diameter, to maintain its shape by conforming to the circular cross section of the strand when the strand rides within the right angle surface thereby preventing the strand 22 from flattening out. When multiple strands are passed over one traverse mechanism 10 the strands 22, normally of a smaller diameter, ride together within the right angle surface when the wire plane is generally normal to the run of the strand to the package 26.,Separation of the strands is maintained while they are in contact with the inclined surfaces of the cams with the result that the strands are only together for that portion of the cycle of the traverse mechanism 10 when they are in contact with the right angle surface. Thus, a ratio of percent separation and 30 percent parallelism exists in the package 26 wound in this manner.

Impetus for the strand in the traverse direction is provided by the inclined surfaces of the wires 50, 52 and 54 indicated respectively by numerals 62, 64 and 66. The rotationally overlapping relation of the inclined surfaces 62, 64 and 66 generate a helical surface, upon rotation, of a varying oblique angle with respect to the axis of rotation. The changing oblique angle generated by the inclined surfaces 62, 64 and 66 provides a means for increasing the impetus imparted to the strand at positions of the strand 22 of higher resistance to traversing, i.e., positions forcing the strand from the neutral or straight line path of the strand 22. In addition, the contact between strand 22 and inclined surfaces 62, 64 and 66 is at a point on the strand 22 other than the point of tangency with the traverse mechanism 10 and occurs as the strand approaches the traverse mechanism 10. Thus, the contact of the inclined surfaces 62, 64 and 66 does not disrupt the essentially continuous contact of the strand 22 with the minor diameter of the traverse mechanism 10.

The above traverse mechanism 10 imparts both a progressive and regressive motion to a strand while it is maintained parallel to the axis of rotation of the traversing mechanism 10 which is maintained parallel to the axis of the package 26 being wound.

Lateral motion of the strand can be considered to be developed by the traversing mechanism as it rotates the several cam elements into engagement with the strand by considering initial contact of the strand 22 to occur essentially when the plane of a cam wire is normal to the line of the strand from the converger 24 to the traverse mechanism 10. The strand is operated upon by this cam wire or element through an arc of its rotation about the axis of shaft 44 from the first plane of initial engagement to a second plane of release of the strand where that second plane is normal to the line of the strand 22 from traverse mechanism 10 to the winding package 26. The diagrams of H68. and 6A through 60 represent the strand-cam relationships as the several cam wires are located in the second plane. Thus these diagrams represent cam-strand relationships upon the departure of the strand from traverse mechanism to package 26.

Wires 50 through 60 are at a position corresponding to point A of FIG. 2. Also illustrated are the positions of strand 22 at 0, 60", 120, 180, 240 and 300 of rotation of the traverse mechanism 10 as viewed at position A. FIGS. 6A through 66 show the progression of positions in 60 rotational increments to illustrate in plan the pattern of the strand 22. FIG. 5 illustrates that all the positions of the strand 22 are parallel to the axis of rotation of the traverse mechanism. Thus, in moving across the face of the traverse mechanism 10, the strand 22 scribes a line which is also parallel to the axis of rotation.

As the cam wire rotates through the are from the first plane to the second plane, its inclined face engages the strand until the strand is laterally displaced to the longitudinal position along the rotational axis at which the minor diameter surface begins. Generally, .a preceding cam element supports the departing strand at the minor diameter as the following cam element in the rotational sequence applies the lateral force of its inclined face to the arriving strand. That force is a function of the angle of inclination of the face. Thus, initiation of motion in a given direction occurs following maximum displacement of the strand from the neutral axis and while the force inherent in the strand tending to return it to neutral is the greatest. At this time the cam face is inclined the minimum amount as for cam wires 50 and 56, since the force it supplied in moving the strand laterally is only that necessary to augment the bias toward neutral in the strand. Maximum velocity of lateral displacement and a requirement to overcome the neutral bias of the strand required as the strand passes the neutral axis dictates a large inclination of the lateral caming face,'as for cam wires 52 and 58, extending toward the neutral axis. As the strand is carried beyond the neutral axis, it counteracts a greater return bias but it should laterally displace the strand at a lower velocity. Therefore, its face inclination is reduced from the maximum, as for wires 54 and 60.

The traverse mechanism has been illustrated in the preferred embodiment in one form, but it is obvious, to those skilled in the art, that the character of the wind of the package may be altered from the embodiment illustrated by changing the size of the traverse mechanism as well as the angles of the inclined surfaces and the position along the cam wire lengths of the limits of the parallel surfaces adjacent their respective incliners to meet particular winding speeds, materials and package sizes. Accordingly, it is to be understood that the present disclosure is illustrative and is not to be read as restrictive.

What we claim is:

l. A traversing mechanism having an axis of rotation and arranged .for displacing a strand which approaches said mechanism along a first line generally normal to a first plane containing said axis and departs from said mechanism along a second line generally normal to a second plane containing said axis, said second plane intersecting said first plane at the axis of rotation to form an acute angle subtended by the strand, said strand displacement being in a cyclically repetitive pattern on both sides of a neutral position which the strand would tend to assume between its first line of approach and its second line of departure from said mechanism if unconstrained, including a pair of opposed cam arrays arranged to engage and laterally displace the strand, means mounting said cam arrays for rotation about said axis of rotation, and means for rotating said mounting means and said cam arrays around said axis, the improvement which comprises: each cam array generally defining, in a plurality of planes extending radially from and angularly spaced about said axis, a first effective surface region parallel to said axis and a second generally helical effective surface region inclined with respect to said axis, said second surface region being inclined with respect to said axis at an acute angle in each of said planes with the acute angle of said second surface region in any one of said planes differing from the acute angle of said second surface region in any other of said planes for the cam array and with said acute angle of said second effective surface region having a magnitude which is greatest for portions of said second surface region adapted to contact said strand closest to said neutral position to urge said strand away from said neutral position and the least for portions of said second surface region adapted to contact said strand farthest from said neutral position to urge said strand toward said neutral position whereby a lateral force is imposed on said Strand by said second surface region to displace said strand laterally to said first surface region so that said strand departs from said first surface region at said second plane.

2. A traversing mechanism according to claim 1 wherein at least one plane extending radially from said axis of rotation and containing effective cam surfaces has a third effective surface region intermediate and contiguous with said first and second regions, and said third effective surface region is essentially perpendicular to said axis of rotation.

3. A traversing mechanism according to claim 1 wherein said first surface region for each of said radially extending planes has a termination at its end proximate said second surface region at a different position along the axis of rotation of said traversing mechanism.

4. A traversing mechanism according to claim 3 wherein said terminations define locations on a generally sinusoidal pattern of lateral positions of the strand centered around said neutral position.

5. A traversing mechanism according to Claim 1 wherein said cam arrays are defined by a plurality of discrete elements.

6. A traversing mechanism according to claim' wherein said elements are disposed with equal angular spacing between successive elements.

7. A traversing mechanism according to claim 6 wherein said cam arrays each comprise at least three of said discrete elements.

8. A traversing mechanism according to claim 7 wherein said discrete elements are of wire.

9. A traversing mechanism according to claim 7 wherein at least two of said discrete elements of each cam array have a third effective surface region intermediate and contiguous with said first and second effective surface regions, and said third effective surface region is essentially perpendicular to said axis of rotation.

10. A traversing mechanism according to claim 9 wherein said discrete elements of each cam array include at least one element wherein said first and second effective surfaces have an intersection and wherein said intersection defines an obtuse angle toward said neutral position whereby said inclined surface portion imparts a lateral force to the strand augmenting the inherent force tending to displace the strand toward its neutral position.

11. A traversing mechanism according to claim 9 wherein said discrete elements having said third effective surface, have said third surface at positions in the lateral traverse cycle of the strand at which larger lateral displacing forces are imposed on said strand.

12. A traverse mechanism according to claim 1 wherein said first effective region of successive planes rotated through said first and second planes have terminations progressively displaced along the axis of rotation whereby the strand is moved laterally along the axis without substantial displacement normal to said axis as cam arrays rotated.

13. A traverse mechanism according to claim 1 wherein the strand is a plurality of glass fiber filaments and said cam arrays are each at least three phosphorbronze wires each formed to define said first and second effective surfaces in said planes extending radially from said axis.

14. A traverse mechanism according to claim 13 wherein the plane of each wire is angularly displaced an equal amount from the planes of its adjacent wires and those wires imparting the greater lateral force on said glass fiber strand have sections extending at right angles to said axis intermediate said first and second effective surfaces whereby said strand is supported normal and parallel to the axis of rotation to minimize the tendency to flatten the strand. 

1. A traversing mechanism having an axis of rotation and arranged for displacing a strand which approaches said mechanism along a first line generally normal to a first plane containing said axis and departs from said mechanism along a second line generally normal to a second plane containing said axis, said second plane intersecting said first plane at the axis of rotation to form an acute angle subtended by the strand, said strand displacement being in a cyclically repetitive pattern on both sides of a neutral position which the strand would tend to assume between its first line of approach and its second line of departure from said mechanism if unconstrained, including a pair of opposed cam arrays arranged to engage and laterally displace the strand, means mounting said cam arrays for rotation about said axis of rotation, and means for rotating said mounting means and said cam arrays around said axis, the improvement which comprises: each cam array generally defining, in a plurality of planes extending radially from and angularly spaced about said axis, a first effective surface region parallel to said axis and a second generally helical effective surface region inclined with respect to said axis, said second surface region being inclined with respect to said axis at an acute angle in each of said planes with the acute angle of said second surface region in any one of said planes differing from the acute angle of said second surface region in any other of said planes for the cam array and with said acute angle of said second effective surface region having a magnitude which is greatest for portions of said second surface region adapted to contact said strand closest to said neutral position to urge said strand away from said neutral position and the least for portions of said second surface region adapted to contact said strand farthest from said neutral position to urge said strand toward said neutral position whereby a lateral force is imposed on said strand by said second surface region to displace said strand laterally to said first surface region so that said strand departs from said first surface region at said second plane.
 2. A traversing mechanism according to claim 1 wherein at least one plane extending radially from said axis of rotation and containing effective cam surfaces has a third effective surface region intermediate and contiguous with said first and second regions, and said third effective surface region is essentially perpendicular to said axis of rotation.
 3. A traversing mechanism according to claim 1 wherein said first surface region for each of said radially extenDing planes has a termination at its end proximate said second surface region at a different position along the axis of rotation of said traversing mechanism.
 4. A traversing mechanism according to claim 3 wherein said terminations define locations on a generally sinusoidal pattern of lateral positions of the strand centered around said neutral position.
 5. A traversing mechanism according to Claim 1 wherein said cam arrays are defined by a plurality of discrete elements.
 6. A traversing mechanism according to claim 5 wherein said elements are disposed with equal angular spacing between successive elements.
 7. A traversing mechanism according to claim 6 wherein said cam arrays each comprise at least three of said discrete elements.
 8. A traversing mechanism according to claim 7 wherein said discrete elements are of wire.
 9. A traversing mechanism according to claim 7 wherein at least two of said discrete elements of each cam array have a third effective surface region intermediate and contiguous with said first and second effective surface regions, and said third effective surface region is essentially perpendicular to said axis of rotation.
 10. A traversing mechanism according to claim 9 wherein said discrete elements of each cam array include at least one element wherein said first and second effective surfaces have an intersection and wherein said intersection defines an obtuse angle toward said neutral position whereby said inclined surface portion imparts a lateral force to the strand augmenting the inherent force tending to displace the strand toward its neutral position.
 11. A traversing mechanism according to claim 9 wherein said discrete elements having said third effective surface, have said third surface at positions in the lateral traverse cycle of the strand at which larger lateral displacing forces are imposed on said strand.
 12. A traverse mechanism according to claim 1 wherein said first effective region of successive planes rotated through said first and second planes have terminations progressively displaced along the axis of rotation whereby the strand is moved laterally along the axis without substantial displacement normal to said axis as cam arrays rotated.
 13. A traverse mechanism according to claim 1 wherein the strand is a plurality of glass fiber filaments and said cam arrays are each at least three phosphor-bronze wires each formed to define said first and second effective surfaces in said planes extending radially from said axis.
 14. A traverse mechanism according to claim 13 wherein the plane of each wire is angularly displaced an equal amount from the planes of its adjacent wires and those wires imparting the greater lateral force on said glass fiber strand have sections extending at right angles to said axis intermediate said first and second effective surfaces whereby said strand is supported normal and parallel to the axis of rotation to minimize the tendency to flatten the strand. 